Objective: Despite advances in suicide prevention implemented throughout the US Department of Veterans Affairs (VA) including the hiring of Suicide Prevention Coordinators (SPCs) at every VA hospital, enhanced monitoring, and the availability of 24-hour crisis hotline services, suicide by veterans remains a critical problem affecting 20 veterans daily. Few empirically based treatment strategies for suicide prevention for postdeployment military personnel exist. This study aimed to test whether dialectical behavior therapy (DBT), one of the few psychosocial treatments with proven efficacy in diminishing suicidal behavior in individuals with personality disorder, can be applied to veterans irrespective of personality diagnosis. Methods: From January 2010 to December 2014, 91 nonpsychotic veterans at high risk for suicide (61 men, 30 women) were randomly assigned to a 6-month treatment trial at a veterans' medical center comparing standard DBT to treatment as usual (TAU) and followed for 6 months after trial completion. Primary outcome was suicide attempts, measured with the Columbia-Suicide Severity Rating Scale, and secondary outcomes were suicide ideation, depression, hopelessness, and anxiety. There were no exclusions pertaining to substance abuse, homelessness, or medical comorbidity. Results: Both DBT and TAU resulted in improvements in suicidal ideation, depression, and anxiety during the course of the 6-month treatment trial that did not differ between treatment arms. Survival analyses for suicide attempts and hospitalizations did not differ between treatment arms. However, DBT subjects utilized significantly more individual mental health services than TAU subjects (28.5 ± 19.6 vs 14.7 ± 10.9, F1,77 = 11.60, P = .001). Conclusions: This study is the first to examine 6-month DBT in a mostly male, veteran population. Increased mental health treatment service delivery, which included enhanced monitoring, outreach, and availability of a designated SPC, did not yield statistically significant differences in outcome for veterans at risk for suicide in TAU as compared to the DBT treatment arm. However, both treatments had difficulty with initial engagement post-hospitalization. Future studies examining possible sex differences and strategies to boost retention in difficult-To-engage, homeless, and substanceabusing populations are indicated.